Variable speed platen printing press



Dec. 13, 1960 A. M. BUTTNER 2,963,966

VARIABLE SPEED PLATEN PRINTING PRESS Filed Oct. 11, 1957 2 Sheets-Sheet 1 A. M. BUTTNER VARIABLE SPEED PLATEN PRINTING PRESS Dec. 13, 1960 2 SheetsSheet 2 Filed Oct. 11, 1957 United States Patent VARIABLE SPEED PLATEN PRINTING PRESS Artur Max Biittner, Heidelberg, Germany, assignor to Schnellpressenfabrik A.G. Heidelberg, Heidelberg, Germany, a corporation of Germany Filed Oct. 11, 1957, Ser. No. 689,510

Claims priority, application Germany May 20, 1950 4 Claims. (Cl. 101-287) The present invention relates to platen-type printing presses and particularly to means for varying the speed of operation of such presses. This application is a continuation-in-part of my application, Serial No. 172,407, filed July 7, 1950, now abandoned.

A platen printing press customarily has a type bed supported on a rigid frame and a platen that is oscillatable about a fixed axis between a printing position in engagement with type held by the type bed and a forward or open position in which paper stock to be printed is fed to and removed from the platen. Oscillation of the platen is effected by a crank and toggle mechanism driven from a main drive shaft rotatably supported by the frame and carrying a drive wheel which is usually a heavy flywheel at the side of the press. The flywheel is driven by a belt from a motor at the rear of the press. Paper being printed is fed to and removed from the platen at a feed station at the front of the press. In an automatic press, feed mechanism is provided for taking sheets of paper from a feed table, positioning them on the platen and then removing the printed sheets from the platen and depositing them on a delivery table. An operator running the press stands in front of it where he can observe and control the feed delivery of paper, the inking of the type and the operation of the platen, and can check the printed sheets coming from the press to see that they are correctly printed.

It is desirable to provide means for varying the speed of a platen press so that item be operated at different speeds according to the work being performed. Moreover, it is desirable to have the speed controllable by an operator stationed at the front of the press. For example in starting up new work, the press is preferably started at low speed. When the operator sees that everything is functioning correctly and he is getting good impressions, it is desirable to speed the press up to increase its production. However, the provision-of a variable speed drive controllable from the front of the press presents difficult problems. Because of its simplicity and reliability, it is desirable to use a constant speed electric motor. over, it is not practical to mount the motor at the front of the machine adjacent the operators position. To provide satisfactory press operation, the speed ratios must be continuously variable over a wide range without interruption of driving effort. This eliminates the use of gear shift transmissions. While continuously variable belt drives are known, they are customarily controllable from a point near the motor and transmission. The problem of controlling such a transmission from the front of the press is complicated by the fact that the speed ratio of such transmissions is subject to variation by changes in load resistance and by shock or vibration.

It is accordingly an object of the present invention to overcome the problems referred to above and provide a platen-type printing press with a continuously variable speed drive controllable by the operator from his normal position at the front of the press. A further object of More- 2,963,966 Patented Dec. 13, 1960 the invention is to avoid fluctuation in speed ratio by reason of the intermittent shock resulting from impact of the platen with the type in the press bed. In accordance with the present invention, these objects are effectively achieved by a simple, economical and reliable construction.

The objects, characteristics and advantages of the present invention will be more fully understood from the following description and claims in conjunction with the accompanying drawings in which:

Fig. 1 is a side view of a platen print ng press embodying the present invention.

Fig. 2 is a plan of the press.

Fig. 3 is a vertical section taken approximately on the line 33 of Fig. 2.

Fig. 4 is a schematic perspective view showing a portion of the speed control mechanism.

The platen printing press shown by way of example in the drawings has a heavy rugged frame 1 with a flanged base portion 1a adapted to be bolted or otherwise securely mounted on a solid foundation or other support. The frame 1 is preferably a steel casting or other construction capable of taking heavy loads and withstanding repeated shock. On the upper part of the frame, there is provided a forwardly facing type bed or chase 2 adapted to receive the type which may be in the form of set type, a plate, block or other desired form. Automatic inking mechanism 3 is provided for applying ink to the type. A platen 4 is oscillatable about a heavy horizontal pivot shaft 5 between a printing position in which the platen is pressed against type held in the type bed 2 and a forward or open position as indicated schematically by broken lines in Fig. 1. Oscillation of the platen is effected by a toggle 6 acting between a toggle pin 7 at the lower end of the platen and a pivot 8. A connecting rod 9 is connected at one end to a central joint 10 of the toggle and at the other end to a crank 11 of a crank shaft 12 which is rotatably supported by the frame 1. A gear 13 fixed on the crank shaft 12 meshes with a pinion on a drive shaft 15 which is parallel to the crank shaft and is likewise rotatably supported by the frame 1. The drive shaft 15 carries a drive wheel 16 which is releasably coupled to the drive shaft by a friction clutch 17. The drive wheel 16 is of large diameter and heavy construction so as to have a high moment of inertia and thus act as a flywheel. The clutch 17 is manually engaged and disengaged by a clutch lever 18 which extends forwardly to the front of the press and is pivotally supported at 19 on a shaft 20 that projects laterally from a forward portion of the frame. The weight of the platen is counterbalanced by a long spring 21 acting between an adjustable support 22 and an arm 23 that projects from the pivot shaft 5 of the platen.

Means is provided at the front of the press forsuc- In an automatic press, mechanism is provided for successively feeding sheets of paper from the stack on the feed table 25 to the platen and removing them from the platen after they have been printed and depositing them on the delivery table 26. Automatic feeding mechanism is illustrated schematically at 27.

The press is driven by an electric motor 30, for example an alternating current motor running at substantially constant speed. The motor 30 has a shaft 31 carrying a pulley 32 comprising two pulley halves 32a and 32b. The pulley halves have conical faces 33 facing one another. One of the pulley halves 32b is fixed to the motor shaft 31, for example by a pin 34, and hasan axially extending sleeve portion 35 surrounding the motor shaft. The outer pulley half 32a has an axially extending sleeve portion 36*that is telescopically slidable on the sleeve portion 35 and'fhas' an inwardly projecting pin 37 engaging'a. longitudinal slot in the sleeve 35 so that the two pulley halves rotate together and with the motor shaft, but the pulley halfj 32av is slidable axially toward and away from the fixed; pulley half. A helical compression spring 38 acts between the movable pulley half 32a and a plate 39 securedto; the end of the motor shaft 31 to exert a selected pressure tending to slide the movable pulley half 32a'toward the fixed pulley half 32b. The motor 30 drives the press by means of a belt 40 which provides a *driving'connection between the motor pulley 32 and the flywheel 16- of the press The belt 40 has inclined edge surfaces which engage the conical surfaces of the pulley halves and a fiat inner surface which engages the outer peripheral surfaces of the flywheel. As described below, means is provided for mounting the motor 39 on the base of the press so as to be movable toward and away from the-flywheel 16. When the motor together with the pulley 32 is moved away from the flywheel 16, the belt 40 is drawn closer to the motor shaft 31 and hence engages the conical faces of the pulley halves nearertheir axis, the movable pulley half 32a being forced away hom the, fixed pulley half 32b sufficiently to accommodate the belt. The effective radius of the pulley 32 is thereby decreased; with a resulting decrease in. the speed at' which the press is driven. Conversely, if'the motor 30 is moved toward the flywheel 16, the spring 38 presses the pulley halves toward one another and the belt 40; is forced outwardly to engage the pulley halves nearer their periphery with a resulting'increase in the press speed. The face of the flywheel is sufliciently wide to accommodate any lateral movement of the beltarising from the fact that only one pulley half is movable.

As illustrated in the drawings, the motor 30 is movably supported by a motor mount41 comprising a pair of angular brackets 41a and 41b. Each of the brackets comprising the motor. support 41 has an approximately horizontal upper arm'portio'n 42 and an approximately vertical downwardly extending lower arm 43, the two arms thus being approximately perpendicular to one another. The upper arms are provided with longitudinally extending slots 44 to receive bolts 45' which secure the motor 30 to the upper arms 42 in selected position and thereby connect thebrackets 41a and 41b into a rigid structure. The motor support 4 1' is pivotally mounted on the base portion of the. press by a pivot shaft 46 which extends through aligned apertures in the lower end pot tions of the downwardly projecting bracket arms 43 and bearing eyes 47, which are a rigid and preferably integral part ofthe press base. In. The bearing eyes 47 are disposed in the angle between the flanged, base portion 1a and the upwardly extending portion of the. frame 1 and are preferably spaced apart a suflicient distance to pro vide a solid support for the pivot shaft 46. Set screws 48 are screwed into tapped holes in the bearing eyes to hold the pivot shaft in fixed position. The lower arms 33 of the motor support are securedin selected position axially of the pivot shaft. 46 by collars 49 while being rotatable on the pivot shaft 46 to-permitthe unit com prising the motor and motor support to rock about the shaft 46 as a pivot. As willbe seen in Fig. 1 the motor 30 is movable away from the flywheel 16 by rocking the motor support about the pivot shaft 46 in a counterclockwise direction and conversely is movable toward the fly wheel 16 by rocking in a clockwise direction. The pivot shaft. 46 and motor shaft 31 are both parallel to the shaft of the flywheel '16. The motor support and its pivotal mounting are sufficiently strong and rugged to assure maintaining this parallel relationship throughout the range of movement of the motor toward and away from the flywheel to vary the speed of the press as described above. a

Control means operable from the front of the press are provided for moving the motor forwardly and rear wadly and holding it securely in selected position. As illustrated in the drawings, the control means comprises a rotatable shaft or spindle 50 that extends forwardly from the motor support to the front of the press. The spindle 50 is preferably inclined upwardly so that its forward end is higher than the rear end and at a con venient height to be reached by an operator standing in front of the press. A rear. end portion of the, spindle 51 is externally threaded and extends through a transverse threaded bore 52 (Fig. 4.)v in a shaft 53 which extends through aligned apertures 54 in the motor supporting brackets 41a and 41b. The apertures for the shaft 53 are located approximately at the junction between the horizontal arms 42 and the downwardly extending vertical arms 43 of the brackets. The shaft 53 is parallel to the pivot shaft 46 and is rotatable relative to the motor support brackets while being held against axial movement for example by collars 55 secured to the shaft 53 for example by set screws. The spindle 50 is perpendicular to the shaft 53 and hence lies in a vertical plane that is perpendicular to the main drive shaft of the press. It extends forwardly from the motor support along one side of the press frame 1. Near its forward end, the spindle 5 0 is rotatably supported by a bearing 57 on the end of a stub shaft 58 which extends through and is rotatably supported by a forwardly projecting portion 1b of the press frame 1. The shaft 58 is perpendicular to the axis of the bearing 57 and parallel to the shaft 53, and is supported by the frame in such a way as to maintain this parallel relationship and to hold the'shaft firmly against transverse movement while permitting rotation about its longitudinal axis. A shoulder 59 and removable collar 60 engage opposite faces of the portion of the frame through which the stub shaft extends to hold the shaft against axial movement. Collars 61 secured to the spindle 50 for example, by pins or set screws, engage opposite ends of the bearing 57 to hold the spindle 50 against axial movement relative to thebearing. A suitable hand wheel or crank 65 having a handle 66 is secured to the forward end of the spindle 50 in a position conveniently accessible to an operator standing in front of the press. As will be seen in Fig. 1 the crank 65 is close to the hadle 18 for controlling the clutch that couples the flywheel 16 to the main shaft of the press. Through engagement of the threaded portion 51 of the spindle with the threaded bore 52 of the shaft 53, said shaft and hence the motor support and motor are moved longitudinally of the spindle when the spindle is rotated. Nuts 56 are set at selected points on the spindle to limit the movement.

The operation of the press and in particular the speed control mechanism will be apparent from the drawings and the foregoing description. Uponrotation of the spindle 50 by the hand crank65, the shaftr53 is displaced in one direction or the other by reason of engagement of the threaded bore 52 of the shaft with the threaded portion 51 of the spindle. This in turn causes the motor support 41 to rock about its pivot shaft 46 and thereby move the motor toward and away from the flywheel. When the motor is moved in a direction away from the flywheel, the belt 40 is drawn, into engagement with the smaller portions of, the conical pulley faces so as to provide a smaller effective pulley radiusv and, thereby decrease the speed' at which the flywheel 16 is driven-the motor speed remaining substantially constant. Conversely, when the motor is moved toward the flywheel 16 by.rotation of the spindle, inthe opposite direction, the pulley halves are pressed, toward .one another by the spring '38 .so that the belt engages larger portions of the conical. pulley faces to increase the, effective radius of the pulley and" thereby drive the flywheel at a higher speed. From Fig. 1 it will be seen that as the motor sup port rocks about the pivot shaft 46, the angular relation of the motor support and the spindle 50 necessarily varies. Variation of this angular relationship is permitted by rotation of the shaft 53 in its bearing supports in the motor brackets. Moreover, since the shaft 53 moves in an arcuate path about the pivot axis 46, the rear end of the spindle 50 is raised or lowered to some extent as the motor support swings forwardly or rearwardly. The raising and lowering of the rear end of the spindle is permitted by rotation of the stub shaft 58 in its bearing support in the press frame. The bearing 57 that supports the forward end portion of the spindle is thus permitted to turn about the axis of the stub shaft 58 so as to remain at all times coaxial with the spindle 50. The mechanism shown and described thus permits the parts to move freely while at the same time moving parts are made to fit closely without appreciable play.

When the motor 30 has been moved to selected position to provide the desired press speed, it is held firmly and securely in that position. It will be apparent that by reason of the weight of the platen and associated mechanism of the press, the reciprocation or oscillation of these parts subjects the press to vibrational forces particularly when the press is operated at high speeds. Moreover, the press is also subjected to repeated shock when the platen engages the press bed with high pressure. This shock is transmitted back through the drive. Variable speed drives employing conical pulleys are sensitive to shock and vibration. If the reactive torque of the driven machine and hence the tension on the driving side of the belt are increased, the belt tends to pull itself in toward the center of the pulley so as to produce a variation in the speed ratio. Moreover, any vibration of the machine transmitted to the motor mount might cause the motor by its inertia to move toward or away from the driven pulley so as to vary the speed ratio. In the construction according to the present invention, these difiiculties are avoided. It will be seen that the motor support 41 is pi otally mounted directly on the rugged frame a of the machine adjacent the flanged base portion 1a which is secured to a solid foundation. Hence any vibration resulting from oscillation from the platen or other moving portions of the press is not transmitted to the motor. Moreover, the construction of the support and of the control mechanism for moving the motor forwardly and rearwardly to vary the speed of the press assures that the motor is held firmly in selected position. The s indle 50 extends in a straight line between the threaded bore in shaft 53 and the bearing 57 on the forward portion of the press frame. Axial movement of the spindle is prevented by engagement of the collars 51 with opposite ends of the bearing 57. The direct interengagement between the threaded portion 51 of the spindle and the threaded bore 52. of the shaft 53 avoids slack or play in the connection. Likewise the rotational support of the shaft 53 in the motor support and the stub shaft 58 in the frame permits free movement of the parts and avoids binding while at the same time avoiding play in the connections. Thus the motor is held firmly in selected position and fluctuations in the driving ratio are avoided. The range of speed through which the press is operable is selected and preset by adjustment of the nuts 57. If any stretching of the belt occurs the stretch can readily be compensated for either by readjusting the nuts 56 or by loosening bolts 55 and moving the motor relative to the motor support (41a and 41b), such adjustment being permitted by the elongated slots provided in the motor support brackets.

It will be seen that the construction in accordance with the invention provides for convenient, safe and eflicient operation of the press. The controls, including the speed control, are located where they are conveniently accessible to an operator standing at the front of the press where he can watch the entire feeding and printing operation. Thus the speed of the press can be varied while the press is in operation to obtain the best printing speed without requiring the operator to leave his station at the front of the press.

While a preferred embodiment of the invention has been shown in the drawings and particularly described, it will be understood that the invention is not limited to this embodiment and that details of construction may be varied within the scope of the appended claims.

What I claim and desire to secure by Letters Patent is:

l. In an automatic platen-type printing press, a rigid frame having a base portion, a front and a rear, a horizontal drive shaft rotatably supported by the frame intermediate the front and rear, a drive wheel on said shaft, a type bed on said frame and facing forwardly, a platen in front of said bed and supported on said frame for oscillation toward and away from said bed, driving connections between said shaft and said platen to oscillate said platen upon rotation of said drive shaft, paper feed means mounted on the front portion of said frame, a motor having a shaft, means supporting said motor on the rear of the frame for movement forwardly and rearwardly, the shaft of said motor being disposed parallel to said drive shaft, a split pulley on said motor shaft comprising two pulley halves with conical faces facing each other, said pulley halves being secured to rotate with the motor shaft and at least one of said pulley halves being axially slidable on said motor shaft, spring means urging said pulley halves toward one another, a belt engaging the conical faces of said pulley halves and the periphery of said drive wheel to provide a driving connection therebetween and means for moving said motor forwardly and rearwardly to vary the zone of engagement of said belt with said pulley halves and thereby vary the speed of the press, comprising a spindle extending forwardly from said motor supporting means to the front of said frame and having a screw-threaded portion, spindle bearing means rotatably supporting said spindle and comprising respectively a bearing mounted on said motor supporting means and a bearing mounted on the front portion of said frame, said bearings being pivotally mounted to turn on horizontal axes perpendicular to the longitudinal axis of said spindle, one of said bearings having internal threads engaging said threaded portion of the spindle and the other of said bearings supporting said spindle against axial movement whereby rotation of said spindle in one direction moves said motor forwardly to increase the speed of the press and rotation of said spindle in the opposite direction moves said motor rearwardly to decrease the speed of the press, and crank means on the forward end of said spindle adjacent said paper feed means, whereby an operator can change the speed of said press without leaving his operating station at the front of the press, said spindle, bearings, motor supporting means and rigid frame cooperating to hold the motor firmly in selected position despite repeated shock incident to oscillation of said platen and engagement of said platen with type held by said type bed.

2. A printing press according to claim 1, in which said motor supporting means comprises a bell-crank bracket having a lower arm pivotally connected at its lower end to the base portion of said frame and an upper arm extending rearwardly from the upper end of said lower arm, and means mounting said motor on said upper arm.

3. A printing press according to claim 1, in which said spindle bearing means mounted on said motor supporting means comprises a shaft rotatably mounted on said bracket parallel to and above the axis of the pivotal connection of said lower bracket arm to said frame, said shaft having a transverse threaded hole through which the threaded portion of said spindle extends, the threads of said hole mating with the threads on said spindle.

4. A printing press according to claim 1, in which said spindle bearing means on the front portion of the frame comprises a stub shaft rotatably supported by said frame with its axis perpendicular to the longitudinal axis of said spindle, a. sleeve bearing on said stub shaft with its axis perpendicular to the axis of said stub shaft, said spindle extending through and being rotatably supported by said sleeve bearing, and collars fixed on said sleeve and engaging opposite ends of said sleeve/bearing to hold said spindle against axial movement.

References (Iited in the file of this patent UNITED STATES PATENTS Winkler Feb. 25, 1919 Young June 11, 1935 LHommedieu Oct. 14, 1941 Morella Mar. 23, 1943 Klaucke Mar. 9, 1948 Root Feb. 14, 1950 Willett Aug; 21, 1951 Rupp Oct. 14, 1952 Larson Apr. 7, 1953 

